The overall objective of this research project remains the isolation of a viral agent from the cultured synovial cells obtained from involved joints of patients with rheumatoid arthritis. Our experimental studies are divided into two major parts: (1) Techniques utilized for direct viral isolation, which include inoculation of rheumatoid joint material into rabbit joints with attempts to recover a viral agent; attempts to rescue virus from rheumatoid synovial cells in culture, both long-term and freshly disaggregated; and hybridization of the DNA extracted from rheumatoid synovial cells with known viral radio-labelled DNA; (2) Attempts to establish an experimental model of rheumatoid arthritis using laboratory animals for cultured synovial cells in which we have established a persistent viral infection. In addition, we are pursuing our attempt to detect a neoantigen in rheumatoid synovial cells. BIBLIOGRAPHIC REFERENCES: Hatcher, V.B., Lazarus, G.S. and Grayzel, A.: Isolation of a cytotoxic human lympyocyte proteinase. Fed. Proc. 1977. Hammerman, D.: Prospects for antiviral therapy in rheumatoid arthritis. In Rheumatoid Arthritis, ed. J.L. Gordon and B.L. Hazleman. Elsevier/North Holland Biomedical Press, Amsterdam, 1977, pp. 143-155.